d3.js 如何将节点动态添加到树中

Question

我正在使用 d3.js 树，并希望动态添加节点，而不是预加载整个树。

我将如何修改以下内容以便在单击节点时动态添加额外的 JSON 节点？ （见下面的链接和下面的代码）

http://mbostock.github.com/d3/talk/20111018/tree.html

因此，我不想预加载整个树，而是希望仅在单击父节点时检索子节点。我可以在切换函数中检索子节点的 json，但是我不知道如何将它们添加到树中。

var m = [20, 120, 20, 120],
    w = 1280 - m[1] - m[3],
    h = 800 - m[0] - m[2],
    i = 0,
    root;

var tree = d3.layout.tree()
    .size([h, w]);

var diagonal = d3.svg.diagonal()
    .projection(function(d) { return [d.y, d.x]; });

var vis = d3.select("#body").append("svg:svg")
    .attr("width", w + m[1] + m[3])
    .attr("height", h + m[0] + m[2])
  .append("svg:g")
    .attr("transform", "translate(" + m[3] + "," + m[0] + ")");

d3.json("flare.json", function(json) {
  root = json;
  root.x0 = h / 2;
  root.y0 = 0;

  function toggleAll(d) {
    if (d.children) {
      d.children.forEach(toggleAll);
      toggle(d);
    }
  }

  // Initialize the display to show a few nodes.
  root.children.forEach(toggleAll);
  toggle(root.children[1]);
  toggle(root.children[1].children[2]);
  toggle(root.children[9]);
  toggle(root.children[9].children[0]);

  update(root);
});

function update(source) {
  var duration = d3.event && d3.event.altKey ? 5000 : 500;

  // Compute the new tree layout.
  var nodes = tree.nodes(root).reverse();

  // Normalize for fixed-depth.
  nodes.forEach(function(d) { d.y = d.depth * 180; });

  // Update the nodes…
  var node = vis.selectAll("g.node")
      .data(nodes, function(d) { return d.id || (d.id = ++i); });

  // Enter any new nodes at the parent's previous position.
  var nodeEnter = node.enter().append("svg:g")
      .attr("class", "node")
      .attr("transform", function(d) { return "translate(" + source.y0 + "," + source.x0 + ")"; })
      .on("click", function(d) { toggle(d); update(d); });

  nodeEnter.append("svg:circle")
      .attr("r", 1e-6)
      .style("fill", function(d) { return d._children ? "lightsteelblue" : "#fff"; });

  nodeEnter.append("svg:text")
      .attr("x", function(d) { return d.children || d._children ? -10 : 10; })
      .attr("dy", ".35em")
      .attr("text-anchor", function(d) { return d.children || d._children ? "end" : "start"; })
      .text(function(d) { return d.name; })
      .style("fill-opacity", 1e-6);

  // Transition nodes to their new position.
  var nodeUpdate = node.transition()
      .duration(duration)
      .attr("transform", function(d) { return "translate(" + d.y + "," + d.x + ")"; });

  nodeUpdate.select("circle")
      .attr("r", 4.5)
      .style("fill", function(d) { return d._children ? "lightsteelblue" : "#fff"; });

  nodeUpdate.select("text")
      .style("fill-opacity", 1);

  // Transition exiting nodes to the parent's new position.
  var nodeExit = node.exit().transition()
      .duration(duration)
      .attr("transform", function(d) { return "translate(" + source.y + "," + source.x + ")"; })
      .remove();

  nodeExit.select("circle")
      .attr("r", 1e-6);

  nodeExit.select("text")
      .style("fill-opacity", 1e-6);

  // Update the links…
  var link = vis.selectAll("path.link")
      .data(tree.links(nodes), function(d) { return d.target.id; });

  // Enter any new links at the parent's previous position.
  link.enter().insert("svg:path", "g")
      .attr("class", "link")
      .attr("d", function(d) {
        var o = {x: source.x0, y: source.y0};
        return diagonal({source: o, target: o});
      })
    .transition()
      .duration(duration)
      .attr("d", diagonal);

  // Transition links to their new position.
  link.transition()
      .duration(duration)
      .attr("d", diagonal);

  // Transition exiting nodes to the parent's new position.
  link.exit().transition()
      .duration(duration)
      .attr("d", function(d) {
        var o = {x: source.x, y: source.y};
        return diagonal({source: o, target: o});
      })
      .remove();

  // Stash the old positions for transition.
  nodes.forEach(function(d) {
    d.x0 = d.x;
    d.y0 = d.y;
  });
}

// Toggle children.
function toggle(d) {

  // I could retrieve the child nodes here, but how to add them to the tree?

  if (d.children) {
    d._children = d.children;
    d.children = null;
  } else {
    d.children = d._children;
    d._children = null;
  }
}

Answer 1

我可以通过在切换函数中添加以下代码来动态添加节点：

$.getJSON(addthese.json, function(addTheseJSON) {
    var newnodes = tree.nodes(addTheseJSON.children).reverse();
    d.children = newnodes[0];
    update(d);
});

注意：我正在使用 jQuery 来检索 json 文件

Answer 2

我是 D3 的新手，但这个原始代码可能会有所帮助。您可以创建一个 JSON 对象并将其推送到树/链接中。那么这只是重新绘制树的问题。

function createTreeNode(source){

var current_node = tree.nodes(source);
var myJSONObject = {"name": "new Node","children": []}; 

if(current_node[0]._children!=null){
current_node[0]._children.push(myJSONObject);
console.log(current_node[0]._children);
source.children = source._children;
source._children = null;
}

else if(current_node[0].children!=null && current_node[0]._children!=null){
current_node[0].children.push(myJSONObject);
console.log(current_node[0].children);
}

else{
current_node[0].children=[]
current_node[0].children.push(myJSONObject);
console.log(current_node[0].children);
}

tree.links(current_node).push(current_node[current_node.length-1]);
navigate_tree(source);}